Mediterranean diet and multiple health outcomes: an umbrella review of meta-analyses of observational studies and randomised trials

A Mediterranean Diet Model in Australia: Strategies for Translating the Traditional Mediterranean Diet into a Multicultural Setting

Substantial evidence supports the effect of the Mediterranean Diet (MD) for managing chronic diseases, although trials have been primarily conducted in Mediterranean populations. The efficacy and feasibility of the Mediterranean dietary pattern for the management of chronic diseases has not been extensively evaluated in non-Mediterranean settings. This paper aims to describe the development of a MD model that complies with principles of the traditional MD applied in a multiethnic context. Optimal macronutrient and food-based composition was defined, and a two-week menu was devised incorporating traditional ingredients with evidence based on improvements in chronic disease management. Strategies were developed for the implementation of the diet model in a multiethnic population. Consistent with the principles of a traditional MD, the MD model was plant-based and high in dietary fat, predominantly monounsaturated fatty acids from extra virgin olive oil. Fruits, vegetables and wholegrains were a mainstay, and moderate amounts of nuts and seeds, fish, dairy and red wine were recommended. The diet encompassed key features of the MD including cuisine, biodiversity and sustainability. The MD model preserved traditional dietary components likely to elicit health benefits for individuals with chronic diseases, even with the adaptation to an Australian multiethnic population.

Mediterranean Diet and Cognitive Status in Free-Living Elderly: A Cross-Sectional Study in Northern Italy

OBJECTIVE

Few data are available on the Italian elderly population with regard to adherence to the Mediterranean diet (MD) and cognitive impairment. Our aim was to investigate adherence to the MD and its association with cognitive function in an Italian urban sample.

METHODS

A cross-sectional study of 279 participants aged ≥ 65 years (80 men, 199 women) was carried out at a nutritional center. Adherence to the MD was evaluated using a 14-item questionnaire. Cognitive function was assessed with the Mini-Mental State Examination (MMSE).

RESULTS

The clinical and nutritional assessments performed revealed 30.1% to have a dietary pattern in accordance with the MD; 13.6% had suspected or mild cognitive impairment (MMSE score ≤ 23). The MD pattern was associated with a lower risk of cognitive impairment (odds ratio [OR] = 0.39; 95% confidence interval [CI], 0.15-0.99; p = 0.045), as was the consumption of wine (OR = 0.37; 95% CI, 0.16-0.84; p = 0.018) and nuts (OR = 0.30; 95% CI, 0.13-0.69, p = 0.005). No association was found with other food groups.

CONCLUSION

A closer adherence to the MD was associated with a better cognitive status. Further cohort studies and randomized controlled trials are warranted.

Olive oil lessened fatty liver severity independent of cardiometabolic correction in patients with non-alcoholic fatty liver disease: A randomized clinical trial

OBJECTIVES

Olive oil has health benefits for the correction of metabolic diseases. We aimed to evaluate the effect of olive oil consumption on the severity of fatty liver and cardiometabolic markers in patients with non-alcoholic fatty liver disease.

METHODS

This randomized, double-blind, clinical trial was conducted on 66 patients with non-alcoholic fatty liver disease. Patients were divided to receive either olive or sunflower oil, each 20 g/d for 12 wk. A hypocaloric diet (-500 kcal/d) was recommended to all participants. Fatty liver grade, liver enzymes, anthropometric parameters, blood pressure, serum lipid profile, glucose, insulin, malondialdehyde, total antioxidant capacity, and interleukin-6 were assessed pre- and postintervention.

RESULTS

Fatty liver grade, weight, waist circumference, and blood pressure significantly decreased in both groups. Sunflower oil significantly reduced serum aspartate and alanine aminotransferases and olive oil only decreased serum aspartate aminotransferase. Fat-free mass and skeletal muscle mass significantly reduced after the consumption of sunflower oil and serum triacylglycerols and fat mass significantly declined after the ingestion of olive oil. Among these variables, only changes in fatty liver grade (-0.29 ± 0.46 in sunflower oil versus -0.75 ± 0.45 in olive oil; P < 0.001), skeletal muscle mass (-0.71 ± 1.36 in sunflower oil versus +0.45 ± 2.8 in olive oil; P = 0.04), and body fat percentage (+0.38 ± 5.2% in sunflower oil versus -3.4 ± 5.5% in olive oil; P = 0.04) were significantly different between the groups.

CONCLUSIONS

Olive oil may alleviate the severity of fatty liver independent of correcting cardiometabolic risk factors. Low-calorie diets may benefit patients with non-alcoholic fatty liver disease additionally through mitigation of obesity, blood pressure, and liver enzymes.

Dietary patterns in association to cancer incidence and survival: concept, current evidence, and suggestions for future research

Assessing diet through dietary patterns has become popular in diet-disease investigations due to the appealing simplicity of expressing several dietary exposures through one variable. Current evidence suggests that there may exist a priori and a posteriori dietary patterns that are consistently associated with reduced all-cause, as well as site-specific cancer risk across different populations. Typical examples include the Mediterranean dietary pattern, the Healthy Eating Index, a number of "healthy" a posteriori dietary patterns, and others. Despite their apparent differences, by inspecting their components it seems that multiple dietary patterns reflect core constituents of a healthy diet. Ongoing research is targeted to: (a) identify the common features underlying the beneficial-for-cancer-prevention dietary patterns, (b) decompose the estimated associations of dietary patterns with cancer risk to the individual associations of their components, and (c) construct dietary patterns for site-specific cancer risk prediction. Results of these and other initiatives could be helpful for public health policy makers and responsible bodies to (a) better formulate relevant messages for informing people about the components of cancer-preventing diets, and (b) promote small changes in eating patterns that can lower cancer risk and improve cancer outcomes.

Mediterranean Diet and Cardiometabolic Diseases in Racial/Ethnic Minority Populations in the United States

The Mediterranean diet (MedDiet) has been recommended to the general population by many scientific organizations as a healthy dietary pattern, based on strong evidence of association with improved cardiometabolic health, including lower risk of cardiovascular disease, diabetes, and obesity. However, most studies have been conducted in Mediterranean or European countries or among white populations in the United States (US), while few exist for non-Mediterranean countries or racial/ethnic minority populations in the US. Because most existing studies evaluating adherence to the MedDiet use population-specific definitions or scores, the reported associations may not necessarily apply to other racial/ethnic populations that may have different distributions of intake. Moreover, racial/ethnic groups may have diets that do not comprise the typical Mediterranean foods captured by these scores. Thus, there is a need to determine if similar positive effects from following a MedDiet are observed in diverse populations, as well as to identify culturally-relevant foods reflected within Mediterranean-like patterns, that can facilitate implementation and promotion of such among broader racial/ethnic groups. In this narrative review, we summarize and discuss the evidence from observational and intervention studies on the MedDiet and cardiometabolic diseases in racial/ethnic minority populations in the US, and offer recommendations to enhance research on MedDiet for such populations.

Low-Calorie Vegetarian Versus Mediterranean Diets for Reducing Body Weight and Improving Cardiovascular Risk Profile: CARDIVEG Study (Cardiovascular Prevention With Vegetarian Diet)

BACKGROUND

Only a few randomized dietary intervention studies that investigated the effects of lacto-ovo vegetarian diet (Vd) in clinically healthy omnivorous subjects are available.

METHODS

We randomly assigned to overweight omnivores with a low-to-moderate cardiovascular risk profile a low-calorie Vd compared with a low-calorie Mediterranean diet (MD), each lasting 3 months, with a crossover design. The primary outcome was the difference in body weight, body mass index, and fat mass changes between the 2 groups. Secondary outcomes were differences in circulating cardiovascular disease risk parameters changes between the 2 groups.

RESULTS

One hundred eighteen subjects (mean age: 51.1 years, females: 78%) were enrolled. The total participation rate at the end of the study was 84.7%. No differences between the 2 diets in body weight were observed, as reported by similar and significant reductions obtained by both Vd (-1.88 kg) and MD (-1.77 kg). Similar results were observed for body mass index and fat mass. In contrast, significant differences between the 2 interventions were obtained for low-density lipoprotein cholesterol, triglycerides, and vitamin B₁₂ levels. The difference between the Vd and MD groups, in terms of end-of-diet values, was recorded at 9.10 mg/dL for low-density lipoprotein cholesterol (P=0.01), 12.70 mg/dL for triglycerides (P<0.01), and 32.32 pg/mL for vitamin B₁₂ (P<0.01). Finally, no significant difference was found between Vd and MD interventions in oxidative stress markers and inflammatory cytokines, except for interleukin-17, which improved only in the MD group. Forty-six participants during the Vd period and 35 during the MD period reached the target values for ≥1 cardiovascular risk factor.

CONCLUSIONS

Both Vd and MD were effective in reducing body weight, body mass index, and fat mass, with no significant differences between them. However, Vd was more effective in reducing low-density lipoprotein cholesterol levels, whereas MD led to a greater reduction in triglyceride levels.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT02641834.

Physical activity and Mediterranean diet based on olive tree phenolic compounds from two different geographical areas have protective effects on early osteoarthritis, muscle atrophy and hepatic steatosis

PURPOSE

Osteoarthitis (OA) leads to progressive loss of articular cartilage, pain and joint disability. An acute injury constitutes an important risk factor for early OA, determining an inflammatory process responsible of cartilage degeneration and muscle atrophy, due to the joint pain and immobility. The study aims to assess the effects of conjugation of physical activity and diet enriched by olive tree compounds [extra virgin olive oil (EVOO) and olive leaf extract (OLE)], on the musculoskeletal system in OA rat model.

METHODS

OA was induced by anterior cruciate ligament transection and confirmed by Mankin and OARSI scores. Rats were subjected to physical activity on treadmill 5 days a week for 10 min daily and fed with experimental diets (standard diet enriched with Sicilian EVOO, Tunisian EVOO and Tunisian EVOO-OLE) for 12 weeks. Immunohistochemistry was used to evaluate IL-6 and lubricin expression in cartilage tissue and ELISA was used to quantify these proteins in serum at different time points. Histology and histomorphometry analysis were done to valuate liver steatosis, muscle atrophy and cartilage pathological changes.

RESULTS

Compared to the OA group, the experimental groups showed general increased lubricin and decreased IL-6 expression, significant muscle hypertrophy and no signs of liver steatosis, suggesting the beneficial effects of physical activity coupled with EVOO-enriched diets on rat articular cartilage. Interestingly, the best result was shown for Sicilian EVOO-enriched diet.

CONCLUSION

In conclusion, the conjugation of physical activity and EVOO-enriched diet determines a significant articular cartilage recovery process in early OA.

What causes psychosis? An umbrella review of risk and protective factors

Psychosis is a heterogeneous psychiatric condition for which a multitude of risk and protective factors have been suggested. This umbrella review aimed to classify the strength of evidence for the associations between each factor and psychotic disorders whilst controlling for several biases. The Web of Knowledge database was searched to identify systematic reviews and meta-analyses of observational studies which examined associations between socio-demographic, parental, perinatal, later factors or antecedents and psychotic disorders, and which included a comparison group of healthy controls, published from 1965 to January 31, 2017. The literature search and data extraction followed PRISMA and MOOSE guidelines. The association between each factor and ICD or DSM diagnoses of non-organic psychotic disorders was graded into convincing, highly suggestive, suggestive, weak, or non-significant according to a standardized classification based on: number of psychotic cases, random-effects p value, largest study 95% confidence interval, heterogeneity between studies, 95% prediction interval, small study effect, and excess significance bias. In order to assess evidence for temporality of association, we also conducted sensitivity analyses restricted to data from prospective studies. Fifty-five meta-analyses or systematic reviews were included in the umbrella review, corresponding to 683 individual studies and 170 putative risk or protective factors for psychotic disorders. Only the ultra-high-risk state for psychosis (odds ratio, OR=9.32, 95% CI: 4.91-17.72) and Black-Caribbean ethnicity in England (OR=4.87, 95% CI: 3.96-6.00) showed convincing evidence of association. Six factors were highly suggestive (ethnic minority in low ethnic density area, second generation immigrants, trait anhedonia, premorbid IQ, minor physical anomalies, and olfactory identification ability), and nine were suggestive (urbanicity, ethnic minority in high ethnic density area, first generation immigrants, North-African immigrants in Europe, winter/spring season of birth in Northern hemisphere, childhood social withdrawal, childhood trauma, Toxoplasma gondii IgG, and non-right handedness). When only prospective studies were considered, the evidence was convincing for ultra-high-risk state and suggestive for urbanicity only. In summary, this umbrella review found several factors to be associated with psychotic disorders with different levels of evidence. These risk or protective factors represent a starting point for further etiopathological research and for the improvement of the prediction of psychosis.

Validation of the English Version of the 14-Item Mediterranean Diet Adherence Screener of the PREDIMED Study, in People at High Cardiovascular Risk in the UK

The aim of this study was to examine the validity of the English version of the PREvencion con DIetaMEDiterranea (PREDIMED) 14-item Mediterranean Diet Adherence Screener (MEDAS), a brief questionnaire assessing adherence to the Mediterranean diet (MedDiet), which was used in the PREDIMED trial for assessment and immediate feedback. This instrument (MEDAS) was administered to 96 adults with a high cardiovascular risk (66% women, mean age 68.3 ± 6.0 years), recruited from general practices in Bristol, UK. Participants then completed a 3-day estimated food record, and the MEDAS was administered again one month later. A MedDiet score (range = 0-14) was calculated from the MEDAS' administrations and food record to assess concurrent validity and test-retest reliability. Predictive validity was assessed by examining the association of the MEDAS-derived score with cardiometabolic risk factors and dietary intakes derived from the food records. The MEDAS-derived MedDiet score was higher by 1.47 points compared to food records (5.47 vs.4.00, p < 0.001), correlated moderately with the record-derived score (r = 0.50, p < 0.001; ICC = 0.53, p < 0.001) and there was borderline fair agreement between the two methods (κ = 0.19, 95% CI 0.07-0.31, p = 0.002; 95% limits of agreement -2.2, 5.1). Exact agreement within score categories and gross misclassificationwere 45.8% and 21.9%, respectively. The distribution of dietary intakes, reported on the food records by the MEDAS-derived total MedDiet score, was in the expected direction, but no association was observed with cardiometabolic risk factors. The two administrations of the MEDAS produced similar mean total MedDiet scores (5.5 vs. 5.4, p = 0.706), which were correlated (r and ICC = 0.69, p < 0.001) and agreed fairly (κ = 0.38, 95% CI 0.24-0.52, p < 0.001; 95% limits of agreement -3.1, 3.2). The English version of the MEDAS has acceptable accuracy and reliability for assessing MedDiet adherence among individuals with a high cardiovascular risk, in the UK, and can be used to rank individuals according to MedDiet adherence in research and practice.

Advances in Understanding the Molecular Basis of the Mediterranean Diet Effect

Increasingly, studies showing the protective effects of the Mediterranean diet (MedDiet) on different diseases (cardiovascular, diabetes, some cancers, and even total mortality and aging indicators) are being published. The scientific evidence level for each outcome is variable, and new studies are needed to better understand the molecular mechanisms whereby the MedDiet may exercise its effects. Here, we present recent advances in understanding the molecular basis of MedDiet effects, mainly focusing on cardiovascular diseases but also discussing other related diseases. There is heterogeneity in defining the MedDiet, and it can, owing to its complexity, be considered as an exposome with thousands of nutrients and phytochemicals. We review MedDiet composition and assessment as well as the latest advances in the genomic, epigenomic (DNA methylation, histone modifications, microRNAs, and other emerging regulators), transcriptomic (selected genes and whole transcriptome), and metabolomic and metagenomic aspects of the MedDiet effects (as a whole and for its most typical food components). We also present a critical review of the limitations of the studies undertaken and propose new analyses and greater bioinformatic integration to better understand the most important molecular mechanisms whereby the MedDiet as a whole, or its main food components, may exercise their protective effects.

Association between Mediterranean diet adherence and dyslipidaemia in a cohort of adults living in the Mediterranean area

The aim of the present study was to determine the association between Mediterranean diet adherence and dyslipidaemia in a cohort of adults living in the Mediterranean area. The cross-sectional study comprised a total sample of 2044 men and women, aged >18 years old from southern Italy. The Mediterranean diet adherence was assessed using a validated score (MEDI-LITE score). Clinical data were investigated and anthropometric examinations were collected using standardised methods. Among included individuals, 18.4% had dyslipidaemia. The percentage of females with dyslipidaemia was higher than males (21.2% vs. 14.6%). Higher adherence to Mediterranean diet was inversely associated with dyslipidaemia (OR: 0.56, 95% Cl: 0.36, 0.86). Similar association was observed in men, but not in women. On the contrary, a positive association was found between dyslipidaemia and current smoking and higher occupational status. Our results support the potential effectiveness of this diet in the prevention of dyslipidaemia and justify future intervention studies.

Stem Cells and Other Emerging Agents as Innovative "Drugs" in Neurodegenerative Diseases: Benefits and Limitations

The brain has a limited process of repair/regeneration linked to the restricted and localized activity of neuronal stem cells. Consequently, it shows a reduced capacity to counteract the age-related loss of neural and glial cells and to repair the consequent injuries/lesions of nervous system. This progressively determines nervous dysfunction and onset/progression of neurodegenerative diseases, which represent a serious social (and economic) problem of our populations. Thus, the research of efficient treatments is encouraged. Stem cell therapy might represent a solution. Today, it, indeed, represents the object of intensive research with the hope of using it, in a near future, as effective therapy for these diseases and preventive treatment in susceptible individuals. Here, we report and discuss the data of the recent studies on this field, underling the obstacles and benefits. We also illustrate alternative measures of intervention, which represent another parallel aim for the care of neurodegenerative pathology-affected individuals. Thus, the road for delaying or retarding these diseases appears hard and long, but the advances might be different.

A Heart-Healthy Diet: Recent Insights and Practical Recommendations

PURPOSE OF REVIEW

The purpose of this study is to review the current evidence on the relationship between diet and heart, giving practical recommendations for cardiovascular prevention.

RECENT FINDINGS

A heart-healthy diet should maximize the consumption of whole grains, vegetables, fruit, and legumes and discourage the consumption of meat and meat products as well as refined and processed foods. Plant-based diets fully meet these criteria, and the evidence supporting the protective effect of these dietary patterns evolved rapidly in recent years. Among plant-based diets, the Mediterranean and vegetarian diets gained the greater interest, having been associated with numerous health benefits such as reduced levels of traditional and novel risk factors and lower risk of cardiovascular disease. These positive effects may be explained by their high content of dietary fiber, complex carbohydrate, vitamins, minerals, polyunsaturated fatty acids, and phytochemicals. Current evidence suggests that both Mediterranean and vegetarian diets are consistently beneficial with respect to cardiovascular disease.